GENESEE COUNTY, Michigan — The well water flowing into your kitchen sink, country club or mobile home park may not be as clean as you think.

Over the past five years, hundreds of drinking water wells tested in Genesee County have had arsenic levels above the limit now deemed safe by the nation’s top environmental agency, according to Department of Environmental Quality data.

The potentially hazardous element was found lurking under local cities and suburbs alike, and in locations as varied as hospice care centers, stores and elementary schools, according to a Flint Journal review of results of 2,688 water samples from nearly 1,000 sites.

More than half the samples contained more than 10 parts per billion of arsenic, the maximum contaminant level set by the U.S. Environmental Protection agency in 2006.

About 220 of the samples tested above the EPA’s old limit of 50 ppb, and more than 50 topped 100 ppb.

“It is a significant public health problem and it’s something we have to deal with,” said James Helmstetter, director of environmental health services for the Genesee County Health Department. “I tell people don’t panic, but it would be prudent if they tested arsenic in their water and found out exactly where it was.”

Arsenic is an element that occurs naturally in rocks and soil, water, air, plants and animals .

Genesee County has been grappling with high arsenic levels for years, and is near the top of the list of Michigan counties in terms of groundwater arsenic levels, said Tim Benton, Lansing district supervisor for the DEQ’s water bureau.

Some owners of contaminated wells have taken steps to filter out the arsenic, which is a known carcinogen in extremely concentrated levels.

Wells that service 25 or more people are required to be in compliance with the 10 ppb federal standard, often forced to install expensive filtration systems to correct the problem — or stop using the water.

But the contaminant continues to plague Genesee County — especially its southern communities.

Unfortunately, that’s also home to the highest concentration of homeowners who rely on private wells — none of which are required to be monitored. .

Flint Township resident Dawn Collins had her well tested earlier this year before moving into her new home, and found out the arsenic level was at 39 ppb.

“That concerned me,” she said, adding that they installed a reverse osmosis system to clean the water. “I don’t know much about it, but I know that it’s not good for you, that’s for sure.”

Fenton Township resident Mary Nordin and her husband Robert learned in 2006 that their well had arsenic at 68 ppb — nearly seven times the EPA’s limit.

She said they buy all their water at the store and they’ve also gone to the doctor to get themselves tested.

“It turned out fine,” said Nordin, who’s lived in their home since 1967. “But we have an old well and we wanted to be sure.”

Most Genesee County communities are supplied water through the Detroit water system, which draws its water from Lake Huron and does not have a problem with arsenic.

Private wells are used throughout the county — sometimes even in areas that have a municipal water system available — but all residents in Argentine, Atlas, Fenton and Forest townships as well as the village of Goodrich rely on well systems, according to the Genesee County drain commissioner’s office.

In all, groundwater wells serve fewer than half of the county’s population, and officials say the number of wells with unsafe arsenic levels has spiked since federal standards became more strict in 2006.

The EPA lowered the allowed level of arsenic in drinking water nationwide from 50 parts per billion to 10 parts per billion.

Joan Rose, an international water expert and Michigan State University professor, said the standard was changed because of research that linked long-term exposure to arsenic to cancer.

“The public should definitely be aware that this is a naturally occurring contaminant that can affect your health and with the new rule we understand there can be these other cancer effects,” said Rose, who sits on an EPA water advisory committee. “The groundwater should be treated to meet the new level to provide a higher degree of safety.”

A few local apartment complexes, subdivisions, nursing homes, churches and schools are just some examples of sites that tested above 10 ppb in the past five years, although some have since tested below the limit after installing filtration systems.

Genesys Hospice Care Center had been testing about 20-24 ppb of arsenic, but has been under the limit since the new standard took effect and it started treating its well water, said Clarence Ball, the center’s certified drinking water operator.

Some of the highest local arsenic levels — some over 200 ppb — were found at the Flint Elks Club Lodge in Davison Township. A staff member who answered the phone said the lodge has installed a system to filter the water, but the golf course superintendent could not be reached for comment.

The new standard prompted some local school systems — where arsenic levels had tested as high as 51 ppb — to temporarily ban drinking the water last year. Lake Fenton, Goodrich, LakeVille and Swartz Creek all had to install expensive filtration systems to come into compliance with the new federal standard.

“If it keeps the water safe and clean to drink for the kids, that’s the most important part,” said Chad Sexton, maintenance supervisor for Swartz Creek schools. “I think it’s safer than a general household well because we go to great lengths to making sure it’s quality drinking water.”

Dave Prince, who works for Culligan of Flint, said he does arsenic testing every week for concerned homeowners. Typically, the results range anywhere from none to 40 ppb and rarely as high as 100 ppb.

“It’s mostly in the southern portion of the county, but we’re finding it everywhere,” he said. “Some people couldn’t care less and some people are very concerned. Arsenic is nasty stuff.”

According to the EPA, human exposure to arsenic can cause both short and long-term health effects, and long-term exposure has been linked to cancer of the bladder, lungs, skin, kidneys, nasal passages, liver and prostate.

But the EPA’s risk assessments assume a person drinks 2 liters of water a day from the tainted source over 70 years — and that sparked lots of debate over the health risks of arsenic.

Goodrich Councilman Ralph Morey said he’s not too concerned about whether arsenic is in his private well.

“I’ve lived here 44 years,” he said. “I’ve never had mine tested and probably never will.”

Still, new guidance from the American Academy of Pediatrics recommends annual testing of private wells that serve children. Young children, the elderly, people with long-term illnesses and unborn babies can be more sensitive to arsenic exposure, according to the state DEQ.

Rose said that the more people who test and report, the better public agencies are equipped to protect public health.

“Basically, we are responsible for ourselves,” she said. “But public health departments and the state should play a leadership role and help homeowners find out where they can get their water tested, how much it will cost and ... how to fix it.”